Gas prices in South Dakota today
Regular gasoline in South Dakota averages $3.69 per gallon as of Monday, July 13, 2026, 18 cents per gallon below the US national average of $3.87 [EIA · 13 Jul 2026]. On-highway diesel is $4.32, -56 cents off the national diesel mean of $4.88. I-29 corridor tracks ND and IA; Black Hills runs 10-15 c/gal higher.
Source: [AAA · 13 Jul 2026] · State excise: 28.0 cents/gal · PADD 2
South Dakota's pump-price cost stack
Every gallon you buy at the pump breaks down into five named slices. For South Dakota today, the stack looks like this:
Crude / refining / distribution shares estimated from EIA Petroleum Marketing Monthly. Federal excise from FHWA Highway Statistics. State excise from the API Motor Fuel Tax Map and Tax Foundation 2026. [EIA · 13 Jul 2026] [API · 13 Jul 2026]
Border-state comparison
For drivers crossing in or out of South Dakota, here is how the neighbours print today:
Use the border comparator to compute the per-tank savings of crossing into a cheaper neighbour, and the round-trip mileage at which the detour pays for itself.
Cheapest metro in South Dakota
Today's cheapest metro in South Dakota is generally Sioux Falls. Within-state spread is typically 20-40 cents per gallon depending on county tax overlays, station brand and distance from the wholesale rack. AAA publishes metro-level detail for South Dakota updated daily.
FAQ
What is the current average price of regular gas in South Dakota?
$3.69 per gallon as of Monday, July 13, 2026, 18 cents below the national average. [AAA · 13 Jul 2026]
What is South Dakota's state gas tax?
28.0 cents per gallon state excise, plus the 18.4 cents federal excise. [API · 13 Jul 2026]
Where is gas cheapest in South Dakota today?
Sioux Falls is typically the cheapest metro. Regional spread is normal at 20-40 cents per gallon.